Wireless power antenna alignment adjustment system for vehicles

ABSTRACT

Exemplary embodiments are directed to wireless charging and wireless power alignment of wireless power antennas associated with a vehicle. A wireless power charging apparatus includes an antenna including first and second orthogonal magnetic elements for detecting a horizontal component of a magnetic field generated from a second charging base antenna. A processor determines a directional vector between the antennas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/082,229 entitled “WIRELESS POWER ANTENNA ALIGNMENT ADJUSTMENT SYSTEMFOR VEHICLES” filed Apr. 7, 2011, which claims priority to: (1) U.S.Provisional Patent Application 61/322,196 entitled “WIRELESS POWERTRANSMISSION IN ELECTRIC VEHICLES BACKGROUND” filed on Apr. 8, 2010; (2)U.S. Provisional Patent Application 61/322,214 entitled “WIRELESS POWERANTENNA ALIGNMENT ADJUSTMENT SYSTEM FOR VEHICLES” filed on Apr. 8, 2010;and (3) U.S. Provisional Patent Application 61/322,221 entitled “VEHICLEGUIDANCE SYSTEM FOR WIRELESS POWER BACKGROUND” filed on Apr. 8, 2010,the disclosures of which are hereby incorporated by reference in theirentireties.

REFERENCE TO CO-PENDING APPLICATION FOR PATENT

This application is also related to the following applications, whichare assigned to the assignee hereof, the disclosures of which areincorporated herein in their entirety by reference: U.S. patentapplication Ser. No. 13/082,211 entitled “WIRELESS POWER TRANSMISSION INELECTRIC VEHICLES” and filed on Apr. 7, 2011, now U.S. Pat. No.9,561,730, issued Feb. 7, 2017 and U.S. patent application Ser. No.15/424,640 entitled “WIRELESS POWER TRANSMISSION IN ELECTRIC VEHICLES”and filed on Feb. 3, 2017, the disclosures of which are herebyincorporated by reference in their entireties.

BACKGROUND Field

The present invention relates generally to wireless power transfer, andmore specifically to devices, systems, and methods related to wirelesspower transfer to vehicles including batteries.

Background

Approaches are being developed that use over-the-air or wireless powertransmission between a transmitter and a receiver coupled to theelectronic device to be charged. Such approaches generally fall into twocategories. One is based on the coupling of plane wave radiation (alsocalled far-field radiation) between a transmit antenna and a receiveantenna on the device to be charged. The receive antenna collects theradiated power and rectifies it for charging the battery. This approachsuffers from the fact that the power coupling falls off quickly withdistance between the antennas, so charging over reasonable distances(e.g., less than 1 to 2 meters) becomes difficult. Additionally, sincethe transmitting system radiates plane waves, unintentional radiationcan interfere with other systems if not properly controlled throughfiltering.

Other approaches to wireless energy transmission techniques are based oninductive coupling between a transmit antenna embedded, for example, ina “charging” mat or surface and a receive antenna (plus a rectifyingcircuit) embedded in the electronic device to be charged. This approachhas the disadvantage that the spacing between transmit and receiveantennas must be very close (e.g., within millimeters). Though thisapproach does have the capability to simultaneously charge multipledevices in the same area, this area is typically very small and requiresthe user to accurately locate the devices to a specific area.

Recently, vehicles have been introduced that include locomotion powerfrom electricity and batteries to provide that electricity. Hybridelectric vehicles include on-board chargers that use power from vehiclebraking and traditional motors to charge the vehicles. Vehicles that aresolely electric must receive the electricity for charging the batteriesfrom other sources. These electric vehicles are conventionally proposedto be charged through some type of wired alternating current (AC) suchas household or commercial AC supply sources.

Efficiency is of importance in a wireless power transfer system due tothe losses occurring in the course of wireless transmission of power.Since wireless power transmission is often less efficient than wiredtransfer, efficiency is of an even greater concern in a wireless powertransfer environment. As a result, there is a need for methods andapparatuses that provide wireless power to electric vehicles.

A wireless charging system for electric vehicles may require transmitand receive antennas to be aligned within a certain degree. Adequatealignment of transmit and receive antennas within an electric vehiclewireless charging system may require proper positioning of an electricvehicle within a parking space, as well as fine tuning of antennalocations after the electric vehicle has been positioned within theparking space. There is a need for systems, devices, and methods relatedto an electric vehicle guidance system. Moreover, a need exists fordevices, systems, and methods for fine alignment of antennas within anelectric vehicle wireless charging system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a hierarchical diagram illustrating how a wireless chargingsystem can be used with a variety of replaceable batteries, each ofwhich may be used in a variety of battery electric vehicles (BEV).

FIG. 2 illustrates a wireless charging system for BEVs equipped with awireless receiver while the BEV is parked near a wireless transmitter.

FIG. 3 is a simplified block diagram of a wireless power charging systemfor a BEV.

FIG. 4 is a more detailed block diagram of a wireless power chargingsystem for a BEV illustrating communication links, guidance links, andalignment systems for the transmit antenna and receive antenna.

FIG. 5 illustrates portions of a distribution system for low voltagepower line communications that may be used in some embodiments of theinvention.

FIG. 6 shows a typical charging process of a Li-Ion battery which may berepresentative for charging a battery that may be used in a BEV.

FIG. 7 illustrates examples of charging times for a battery that may beused in a BEV.

FIG. 8 illustrates a frequency spectrum showing various frequencies thatmay be available for wireless charging of BEVs.

FIG. 9 illustrates some possible frequencies and transmission distancesthat may be useful in wireless charging of BEVs.

FIG. 10 illustrates transmit and receive loop antennas showing magneticfield strength relative to radius of the antennas.

FIGS. 11A and 11B illustrate magnetic fields around a loop antenna andaccompanying ferrite backing.

FIG. 12 is a graph illustrating possible inductance values for variousthicknesses of a ferrite backing as part of a wireless power antenna.

FIG. 13 is a graph illustrating possible ferrite loss values for variousthicknesses of a ferrite backing as part of a wireless power antenna.

FIG. 14 shows a simplified diagram of a replaceable contactless batterydisposed in a BEV.

FIGS. 15A-15D are more detailed diagrams of a wireless power antenna andferrite material placement relative to a battery.

FIG. 16 is a simplified block diagram of portions of a battery system ina BEV equipped to wirelessly receive or transmit power.

FIG. 17 illustrates a parking lot comprising a plurality of parkingspaces and a charging base positioned within each parking space, inaccordance with an embodiment of the present invention.

FIG. 18 illustrates a pair of tire stops positioned within a parkingspace having a charging base positioned therein.

FIG. 19 illustrates a BEV approaching a charging spot by using aguidance system, in accordance with an exemplary embodiment of thepresent invention.

FIG. 20 depicts a block diagram of a portion of a guidance system, inaccordance with an exemplary embodiment of the present invention.

FIG. 21 illustrates a receive antenna, according to an exemplaryembodiment of the present invention.

FIG. 22 depicts another receive antenna, according to an exemplaryembodiment of the present invention.

FIG. 23 depicts a magnetic field generated by a transmit antenna of acharging base, in accordance with an exemplary embodiment of the presentinvention.

FIG. 24 illustrates a side-view of a receive antenna and a charging baseemitting a magnetic field, according to an exemplary embodiment of thepresent invention.

FIG. 25 illustrates a top-down view of a receive antenna positionedwithin a magnetic field, according to an exemplary embodiment of thepresent invention.

FIG. 26 illustrates four ultra wide band transponders for use within atriangulation process, according to an exemplary embodiment of thepresent invention.

FIG. 27 is a flowchart illustrating a method, in accordance with anexemplary embodiment of the present invention.

FIG. 28A illustrates various obstructions that may be encountered by avehicle, which may require chassis clearance.

FIGS. 28B and 28C illustrate a wireless power antenna located within acavity of the underside of the chassis of a vehicle according to anexemplary embodiment of the present invention.

FIG. 29A illustrates a tool which may be used to drill a hole in theground, in which a charging base may be at least partially embeddedaccording to an exemplary embodiment of the present invention.

FIG. 29B illustrates several variants of embedding a charging baseaccording to exemplary embodiments of the present invention.

FIG. 29C illustrates a charging base located fully below the surface ofthe ground according to an exemplary embodiment of the presentinvention.

FIG. 29D illustrates a cover with collar positioned over a charging baseaccording to an exemplary embodiment of the present invention.

FIG. 30A-30C illustrate a vehicle including a wireless power antennapositioned over a charging base including a wireless power antennaaccording to an exemplary embodiment of the present invention.

FIGS. 31A-31G illustrate several variants for fine alignment adjustmentaccording to various exemplary embodiments of the present invention.

FIG. 32 illustrates possible locations in the X and Y direction that amechanical device may adjust the position of a wireless power antennaaccording to an exemplary embodiment of the present invention.

FIG. 33 illustrates a mechanical solution for a wireless power antennathat is located within a cavity of the underside of a vehicle accordingto an exemplary embodiment of the present invention.

FIG. 34 illustrates another mechanical solution in which the wirelesspower antenna may be repositioned by a gear shaft operably coupled to adrive mechanism according to an exemplary embodiment of the presentinvention.

FIG. 35A illustrates a charging base 3520 experiencing heavy loadingfrom the weight of a vehicle.

FIGS. 35B and 35C illustrate a charging base including a reinforcedcover according to an exemplary embodiment of the present invention.

FIGS. 36A-36D illustrate a vehicle including a wireless power batteryunit and the wireless power antenna configured to be repositioned in theX, Y, and Z directions in various combinations according to an exemplaryembodiment of the present invention.

FIG. 37A-37B illustrate a fine alignment adjustment system for awireless power charging system for a vehicle according to an alternativeexemplary embodiment of the present invention.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of exemplary embodiments of thepresent invention and is not intended to represent the only embodimentsin which the present invention can be practiced. The term “exemplary”used throughout this description means “serving as an example, instance,or illustration,” and should not necessarily be construed as preferredor advantageous over other exemplary embodiments. The detaileddescription includes specific details for the purpose of providing athorough understanding of the exemplary embodiments of the invention. Itwill be apparent to those skilled in the art that the exemplaryembodiments of the invention may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the novelty of theexemplary embodiments presented herein.

The term “wireless power” is used herein to mean any form of energyassociated with electric fields, magnetic fields, electromagneticfields, or otherwise that is transmitted from a transmitter to areceiver without the use of physical electromagnetic conductors.

Moreover, the term “wireless charging” is used herein to mean providingwireless power to one or more electrochemical cells or systems includingelectrochemical cells for the purpose of recharging the electrochemicalcells.

The term “battery electric vehicle” (BEV) is used herein to mean avehicle that includes, as part of its locomotion abilities, electricalpower derived from one or more rechargeable electrochemical cells. Asnon-limiting examples, some BEVs may be hybrid electric vehicles thatinclude on-board chargers that use power from vehicle deceleration andtraditional motors to charge the vehicles, other BEVs may draw alllocomotion ability from electrical power.

Exemplary embodiments of the invention include methods and apparatusesthat provide wireless power to electric vehicles.

FIG. 1 is a hierarchical diagram illustrating how a wireless chargingsystem can be used with a variety of replaceable batteries, each ofwhich may be used in a variety of battery electric vehicles. Starting atthe top, there may be many different models of BEVs. However, groups ofvehicle models may be adapted to use only a limited number ofreplaceable battery units, such as Electric Vehicle (EV) battery type A,EV battery type B, and EV battery type C. As non-limiting examples,these different battery types may be configured based on needed capacityof the batteries, space required for the batteries, form factor for thebatteries, size of wireless power antennas, and form factor for wirelesspower antennas. With the battery types limited, particularly, the size,placement, and form factor of the wireless antennas, a single wirelesspower delivery solution can be provided that will provide near-fieldwireless coupling to the various battery types.

A battery integrated solution may ease adoption of wireless charging byEV manufacturers as this solution will have only minor impact on theelectrical and mechanical design of an EV. Once widely accepted andstandardized, only a relatively small number of EV battery types willneed to be in circulation. Limiting the battery types will simplifycustomization of a wireless BEV charging solution as the number ofbattery types will be much smaller than the number of EV models thatwill be introduced into the market in the future.

Furthermore, limited battery types may enable an existing EV model to beretrofitted for wireless charging. This retrofitting could be simplyperformed by replacing a conventional battery in an EV with a newbattery that integrates wireless charging and that behaves as theoriginal battery at all its other interfaces. In addition, wirelesspower battery types may be configured with a wireless and contactlesscharging interface to the rest of the vehicles allowing for easy batteryswapping and non-contact recharging of batteries, which may include someadvantages in regards to reliability, mechanical wear out and safety.

FIG. 2 illustrates a wireless charging system for wireless chargingenabled BEVs 102 while the BEV is parked near a wireless charging base(CB) 104. Two vehicles 102 are illustrated in a parking area 106 andparked over corresponding CBs 104. A local distribution center 108 isconnected to a power backbone and is configured to provide anAlternating Current (AC) or a Direct Current (DC) supply to powerconversion systems 112 as part of the CBs 104. The CBs 104 also includewireless power antennas 114 for generating or picking-up a near-fieldradiation. Each vehicle includes batteries, a BEV power conversion andcharging system 116 and a wireless power antenna 118 interacting withthe CB antenna 114 via the near-field. In some exemplary embodiments theBEV antenna 118 may be aligned with the CB antenna 114 and, therefore,disposed within the near-field region simply by the driver positioningthe vehicle correctly relative to the CB antenna 114. In other exemplaryembodiments, the driver may be given visual feedback, auditory feedback,or combinations thereof to determine when the vehicle is properly placedfor wireless power transfer. In yet other exemplary embodiments, thevehicle may be positioned by an autopilot system, which may move thevehicle back and forth (e.g., in zig-zag movements) until an alignmenterror has reached a tolerable value. This may be performed automaticallyand autonomously by the vehicle without or with only minimal driverintervention provided that the vehicle is equipped with a servo steeringwheel, ultrasonic sensors all around and artificial intelligence. Instill other exemplary embodiments, the BEV antenna 118, the CB antenna114, or a combination thereof may include means for displacing andmoving the antennas relative to each other to more accurately orientthem and develop a more optimum near-field coupling therebetween.

The CBs 104 may be located in a variety of locations. As non-limitingexamples, some suitable locations are a parking area at a home of thevehicle owner, parking areas reserved for BEV wireless charging modeledafter conventional petroleum-based filling stations, and parking lots atother locations such as shopping centers and places of employment.

These BEV charging stations may provide numerous benefits, such as, forexample:

-   -   Convenience: charging can be performed automatically virtually        without driver intervention and manipulations.    -   Reliability: there may be no exposed electrical contacts and no        mechanical wear out.    -   Safety: manipulations with cables and connectors may not be        needed, and there may be no cables, plugs, or sockets that may        be exposed to moisture and water in an outdoor environment.    -   Vandalism resistant: There may be no sockets, cables, and plugs        visible nor accessible.    -   Availability: if BEVs will be used as distributed storage        devices to stabilize the grid. Availability can be increased        with a convenient docking-to-grid solution enabling Vehicle to        Grid (V2G) capability.    -   Esthetical and non-impedimental: There may be no column loads        and cables that may be impedimental for vehicles and/or        pedestrians.

As a further explanation of the V2G capability, the wireless powertransmit and receive capabilities can be configured as reciprocal suchthat the CB 104 transfers power to the BEV 102 and the BEV transferspower to the CB 104. This capability may be useful for powerdistribution stability by allowing BEVs to contribute power to theoverall distribution system in a similar fashion to how solar-cell powersystems may be connected to the power grid and supply excess power tothe power grid.

FIG. 3 is a simplified block diagram of a wireless power charging systemfor a BEV. Exemplary embodiments described herein use capacitivelyloaded wire loops (i.e., multi-turn coils) forming a resonant structurethat is capable to efficiently couple energy from a primary structure(transmitter) to a secondary structure (receiver) via the magnetic nearfield if both primary and secondary are tuned to a common resonancefrequency. The method is also known as “magnetic coupled resonance” and“resonant induction.”

To enable wireless high power transfer, some exemplary embodiments mayuse a frequency in the range from 20-60 kHz. This low frequency couplingmay allow highly efficient power conversion that can be achieved usingstate-of-the-art solid state devices. In addition, there may be lesscoexistence issues with radio systems compared to other bands.

In FIG. 3, a conventional power supply 132, which may be AC or DC,supplies power to the CB power conversion module 134 assuming energytransfer towards vehicle. The CB power conversion module 134 drives theCB antenna 136 to emit a desired frequency signal. If the CB antenna 136and BEV antenna 138 are tuned to substantially the same frequencies andare close enough to be within the near-field radiation from the transmitantenna, the CB antenna 136 and BEV antenna 138 couple such that powermay be transferred to the BEV antenna 138 and extracted in the BEV powerconversion module 140. The BEV power conversion module 140 may thencharge the BEV batteries 142. The power supply 132, CB power conversionmodule 134, and CB antenna 136 make up the infrastructure part 144 of anoverall wireless power system 130, which may be stationary and locatedat a variety of locations as discussed above. The BEV battery 142, BEVpower conversion module 140, and BEV antenna 138 make up a wirelesspower subsystem 146 that is part of the vehicle or part of the batterypack.

In operation, assuming energy transfer towards the vehicle or battery,input power is provided from the power supply 132 such that the CBantenna 136 generates a radiated field for providing the energytransfer. The BEV antenna 138 couples to the radiated field andgenerates output power for storing or consumption by the vehicle. Inexemplary embodiments, the CB antenna 136 and BEV antenna 138 areconfigured according to a mutual resonant relationship and when theresonant frequency of the BEV antenna 138 and the resonant frequency ofthe CB antenna 136 are very close, transmission losses between the CBand BEV wireless power subsystems are minimal when the BEV antenna 138is located in the “near-field” of the CB antenna 136.

As stated, an efficient energy transfer occurs by coupling a largeportion of the energy in the near-field of a transmitting antenna to areceiving antenna rather than propagating most of the energy in anelectromagnetic wave to the far field. When in this near-field acoupling mode may be developed between the transmit antenna and thereceive antenna. The area around the antennas where this near-fieldcoupling may occur is referred to herein as a near field coupling-moderegion.

The CB and the BEV power conversion module may both include anoscillator, a power amplifier, a filter, and a matching circuit forefficient coupling with the wireless power antenna. The oscillator isconfigured to generate a desired frequency, which may be adjusted inresponse to an adjustment signal. The oscillator signal may be amplifiedby the power amplifier with an amplification amount responsive tocontrol signals. The filter and matching circuit may be included tofilter out harmonics or other unwanted frequencies and match theimpedance of the power conversion module to the wireless power antenna.

The CB and BEV power conversion module may also include, a rectifier,and switching circuitry to generate a suitable power output to chargethe battery.

BEV and CB antennas used in exemplary embodiments may be configured as“loop” antennas, and more specifically, multi-turn loop antennas, whichmay also be referred to herein as a “magnetic” antenna. Loop (e.g.,multi-turn loop) antennas may be configured to include an air core or aphysical core such as a ferrite core. An air core loop antenna may allowthe placement of other components within the core area. Physical coreantennas may allow development of a stronger electromagnetic field.

As stated, efficient transfer of energy between a transmitter andreceiver occurs during matched or nearly matched resonance between atransmitter and a receiver. However, even when resonance between atransmitter and receiver are not matched, energy may be transferred at alower efficiency. Transfer of energy occurs by coupling energy from thenear-field of the transmitting antenna to the receiving antenna residingin the neighborhood where this near-field is established rather thanpropagating the energy from the transmitting antenna into free space.

The resonant frequency of the loop antennas is based on the inductanceand capacitance. Inductance in a loop antenna is generally simply theinductance created by the loop, whereas, capacitance is generally addedto the loop antenna's inductance to create a resonant structure at adesired resonant frequency. As a non-limiting example, a capacitor maybe added in series with the antenna to create a resonant circuit thatgenerates a magnetic field. Accordingly, for larger diameter loopantennas, the size of capacitance needed to induce resonance decreasesas the diameter or inductance of the loop increases. It is further notedthat inductance may also depend on a number of turns of a loop antenna.Furthermore, as the diameter of the loop antenna increases, theefficient energy transfer area of the near-field increases. Of course,other resonant circuits are possible. As another non-limiting example, acapacitor may be placed in parallel between the two terminals of theloop antenna (i.e., parallel resonant circuit).

Exemplary embodiments of the invention include coupling power betweentwo antennas that are in the near-fields of each other. As stated, thenear-field is an area around the antenna in which electromagnetic fields(also referred to herein as near field radiation) exist but may notpropagate or radiate away from the antenna. Near-field coupling-moderegions are typically confined to a volume that is near the physicalvolume of the antenna e.g. within a radius of one sixth of thewavelength. In the exemplary embodiments of the invention, magnetic typeantennas such as single and multi-turn loop antennas are used for bothtransmitting and receiving since magnetic near-field amplitudes inpractical embodiments tend to be higher for magnetic type antennas incomparison to the electric near-fields of an electric-type antenna(e.g., a small dipole). This allows for potentially higher couplingbetween the pair. Another reason for relying on a substantially magneticfield is its low interaction with non-conductive dielectric materials inthe environment and the safety issue. Electric antennas for wirelesshigh power transmission may involve extremely high voltages.Furthermore, “electric” antennas (e.g., dipoles and monopoles) or acombination of magnetic and electric antennas is also contemplated.

FIG. 4 is a more detailed block diagram of a generic wireless powercharging system 150 for a BEV illustrating communication links 152,guidance links 154, and alignment systems 156 for the CB antenna 158 andBEV antenna 160. As with the exemplary embodiment of FIG. 3 and assumingenergy flow towards BEV, in FIG. 4 the CB power conversion unit 162receives AC or DC power from the CB power interface 164 and excites theCB antenna 158 at or near its resonant frequency. The BEV antenna 160,when in the near field coupling-mode region, receives energy from thenear field coupling mode region to oscillate at or near the resonantfrequency. The BEV power conversion unit 166 converts the oscillatingsignal from the receive antenna 160 to a power signal suitable forcharging the battery.

The generic system may also include a CB communication unit 168 and aBEV communication unit 170, respectively. The CB communication unit 168may include a communication interface to other systems (not shown) suchas, for example, a computer, and a power distribution center. The BEVcommunication unit 170 may include a communication interface to othersystems (not shown) such as, for example, an on-board computer on thevehicle, other battery charging controller, other electronic systemswithin the vehicles, and remote electronic systems.

The CB and BEV communication units may include subsystems or functionsfor specific application with separate communication channels therefore.These communications channels may be separate physical channels or justseparate logical channels. As non-limiting examples, a CB alignment unit172 may communicate with a BEV alignment unit 174 to provide a feedbackmechanism for more closely aligning the CB antenna 158 and BEV antenna160, either autonomously or with operator assistance. Similarly, a CBguide unit 176 may communicate with a BEV guide unit 178 to provide afeedback mechanism to guide an operator in aligning the CB antenna 158and BEV antenna 160. In addition, there may be a separategeneral-purpose communication channel 152 including CB communicationunit 180 and BEV communication unit 182 for communicating otherinformation between the CB and the BEV. This information may includeinformation about EV characteristics, battery characteristics, chargingstatus, and power capabilities of both the CB and the BEV, as well asmaintenance and diagnostic data. These communication channels may beseparate physical communication channels such as, for example,Bluetooth, zigbee, cellular, etc.

In addition, some communication may be performed via the wireless powerlink without using specific communications antennas. In other words thecommunications antenna and the wireless power antenna are the same.Thus, some exemplary embodiments of the CB may include a controller (notshown) for enabling keying type protocol on the wireless power path. Bykeying the transmit power level (Amplitude Shift Keying) at predefinedintervals with a predefined protocol, the receiver can detect a serialcommunication from the transmitter. The CB power conversion module 162may include a load sensing circuit (not shown) for detecting thepresence or absence of active BEV receivers in the vicinity of thenear-field generated by the CB antenna 158. By way of example, a loadsensing circuit monitors the current flowing to the power amplifier,which is affected by the presence or absence of active receivers in thevicinity of the near-field generated by CB antenna 158. Detection ofchanges to the loading on the power amplifier may be monitored by thecontroller for use in determining whether to enable the oscillator fortransmitting energy, to communicate with an active receiver, or acombination thereof.

BEV circuitry may include switching circuitry (not shown) for connectingand disconnecting the BEV antenna 160 to the BEV power conversion unit166. Disconnecting the BEV antenna not only suspends charging, but alsochanges the “load” as “seen” by the CB transmitter, which can be used to“cloak” the BEV receiver from the transmitter. If the CB transmitterincludes the load sensing circuit, it can detect these load changes.Accordingly, the CB has a mechanism for determining when BEV receiversare present in the CB antenna's near-field.

FIG. 5 illustrates portions of a power distribution system 200 enabledfor low voltage power line communications that may be used in someembodiments of the invention. The CB may be linked to a power linecommunication system through a power distribution 182 to provide PowerLine Communications (PLC) via its external CB-COM interface thatsupports the relevant PLC standard. The PLC node communicating with theexternal CB-COM interface may be integrated in an electricity (energy)meter 184. In many countries and particularly in Europe, PLC may play animportant role as part of an Automated Metering Infrastructure (AMI) andfor Smart Grid applications. An AMI may include elements such as:Automatic Meter Reading (AMR) of electricity, gas, water, heat; energyand water use profiling; demand forecasting; and demand side management.Furthermore, with exemplary embodiments of the invention, AMI mayinclude management of V2G for BEVs. As a non-limiting example, anin-house PLC system may be configured as part of a home area network forhome automation applications. Some non-limiting frequencies for PLCnodes may be in Band B (95-125 kHz) or Band C (125-140 kHz).

Wireless power charging in BEVs may be adapted to many different batterycapabilities and technologies. For some exemplary embodiments,information about the battery capabilities and technologies may beuseful in determining charging characteristics and charging profiles.Some non-limiting examples of battery capabilities are; battery charge,battery energy, battery voltage, battery capacity, battery chargecurrent, battery charge power, and charging capabilities.

Many different batteries and electrochemical cell technologies may beused in BEVs. Some non-limiting examples of suitable electrochemicalcells are, Lithium Ion, Lithium polymer, and lead-acid type batteries.Li-Ion cells may provide high energy density due to a high battery packvoltage (e.g., 400 V). Lead acid cells may provide high energy densitydue to high battery capacity (e.g. 180 Ah). Currently, there has been atrend to Li-Ion cells because they provide a high energy-density andhigh power-density. However, exemplary embodiments of the presentinvention may be used in other rechargeable electrochemical orelectromechanical (e.g. flywheel) cells and even future rechargeableelectrochemical or electromechanical cells.

FIG. 6 illustrates a typical charging process of a Li-Ion battery thatmay be representative for a battery that may be used in a BEV. The graphillustrates charge current versus charge time, cell voltage, and chargecapacity. During a first phase, substantially constant current may beapplied to the battery as the charge capacity is increasing at arelatively high rate. During a second phase, a substantially constantvoltage may be applied as the charge capacity nears full charge. FIG. 6illustrates an example charge scenario for charging a battery at itsrated capacity (often referred to as 1C). Other fast charge scenariosmay be used, such as rates faster than 1C (e.g., 2C, 3C, etc).

FIG. 7 illustrates examples of charging times for a battery that may beused in a BEV. A stored energy of 25 kWh is shown as one example of acharge capacity for a typical battery in a BEV. Depending on the poweravailable, the charge time to full capacity may be as low as about 1.25hours with a high delivery capability of about 21 kW, about 3.5 hoursfor an accelerated delivery capability of about 7 kW, about 8.5 hoursfor a normal delivery capability of about 3 kW, and about 12.5 hours fora domestic delivery capability of about 2 kW. FIG. 7 is intended as anexample only to show ranges of charging times and how they may beadapted to wireless power delivery capabilities.

FIG. 8 illustrates a frequency spectrum showing various frequencies thatmay be available and suitable for wireless charging of BEVs. Somepotential frequency ranges for wireless high power transfer to BEVsinclude: VLF in a 3 kHz to 30 kHz band, lower LF in a 30 kHz to 150 kHzband (for ISM-like applications) with some exclusions, HF 6.78 MHz(ITU-R ISM-Band 6.765-6.795 MHz), HF 13.56 MHz (ITU-R ISM-Band13.553-13.567), and HF 27.12 MHz (ITU-R ISM-Band 26.957-27.283).

FIG. 9 illustrates some possible frequencies and transmission distancesthat may be useful in wireless charging of BEVs. Some exampletransmission distances that may be useful for BEV wireless charging areabout 30 mm, about 75 mm, and about 150 mm Some exemplary frequenciesmay be about 27 kHz in the VLF band and about 135 kHz in the LF band.

Many consideration must be taken into account on determining a suitablefrequency beyond just the resonance characteristics and coupling-moderegion of the receive and transmit antennas. Wireless power frequenciesmay interfere with frequencies used for other applications. Asnon-limiting examples, there may be VLF/LF coexistence issues with powerline frequencies, audible frequencies and communication frequencies.Some non-limiting examples where coexistence may be an issue for VLF andLF are: frequencies for radio clocks, frequencies for LW AM broadcastsand other radio services, cross-coupling to ISDN/ADSL and ISDN/xDSLcommunication channels, electronic vehicle immobilization systems, RFID(Radio Frequency Identification) systems, EAS (Electronic ArticleSurveillance) systems, on-site paging, Low Voltage PLC systems, medicalimplants (cardiac pacemakers, etc.), audio systems and acoustic emissionperceivable by humans and animals.

Some non-limiting examples where coexistence may be an issue for HFfrequencies are industrial, scientific and medical (ISM) radio bands,such as: 6.78 MHz for remote control applications and RFID in FDX or HDXmode with continuous energy transfer; 13.56 MHz for RFID in FDX or HDXmode with continuous energy transfer as well as portable device wirelesspower; and 27.12 MHz for Railway applications (Eurobalise 27.095 MHz),Citizen band radio, and remote control (e.g., models, toys, garage door,computer mouse, etc.).

FIG. 10 illustrates transmit and receive loop antennas showing fieldstrength relative to radius of the antennas. Antenna structures with aradius larger or smaller than an optimum radius generate higher fieldstrength in the vicinity of the antenna for a given transferred power.H-field strength increases linearly with increasing power transferdistance and for a given transferred power provided that the antennaradius is proportionally increased thus always optimum.

FIGS. 11A and 11B illustrate electromagnetic fields around a loopantenna and accompanying ferrite backing. A transmit antenna includes awire loop 1130, which may comprise a multi-turn wire loop, and a ferritebacking 1120 and a receive antenna includes a wire loop 1180 and aferrite backing 1170. At VLF and LF frequencies, a ferrite backing maybe useful for intensifying the magnetic field 1140 in the space betweenthe antennas thus for enhanced coupling. As shown in FIG. 11A, if theseparation between the antenna coils 1130 and 1180 and the ferritebackings 1120 and 1170 is reduced to 0 cm, the coupling coefficientbetween the transmit antenna and receive antenna decreases slightly.Consequently, there may be an ideal separation between the antenna coils1130 and 1180 and the ferrite backings 1120 and 1170. FIG. 11B,illustrates a small separation between the antenna coils 1130 and 1180and the ferrite backings 1120 and 1170. In addition, a reduced spacingis illustrated between the antenna coils 1130 and 1180 and theirrespective ferrite backings 1120 and 1170. For smaller transmissiondistances (e.g., 3 cm), the performance gain of ferrite backing may beless because the coupling coefficient is very high already.

FIG. 12 is a graph illustrating possible inductance values for variousthicknesses of a ferrite backing as part of a wireless power antenna. Inthe exemplary embodiment for FIG. 12 the ferrite backing is about 0.5 cmfrom the coil. It can be seen that inductance does not changeconsiderably (i.e., about 5%) with a thickness change for the ferritebacking between about 5 mm and 10 mm.

FIG. 13 is a graph illustrating possible ferrite loss values for variousthicknesses of a ferrite backing as part of a wireless power antenna. Inthe exemplary embodiment for FIG. 12 the ferrite backing is about 0.5 cmfrom the coil. It can be seen that losses increase rapidly (i.e., about185%) with a thickness change for the ferrite backing between about 5 mmand 10 mm. The resulting loss may decrease the Q factor. As a result, atrade-off may need to be made between performance relative toconsiderations such as volume, weight, and cost.

FIG. 14 shows a simplified diagram of a replaceable battery disposed ina battery electric vehicle (BEV) 220. In this exemplary embodiment, TheBEV side of the wireless energy transfer system is an integral part ofthe vehicles battery unit 222. Present movements towards standardized EVbatteries may enable easy and fast replacement in so-called batteryswapping (or switching) stations. As shown in FIG. 14, the shape andplacement of the battery unit 222 are illustrative of one exemplaryembodiment. Many other configurations are possible. As a non-limitingexample, the bulk of the battery may be below the rear seat.

However, the low battery position may be useful for a battery unit thatintegrates a wireless power interface and that can receive power from acharger embedded in the ground. Fast battery replacement will likelycontinue to coexist with corded and wireless BEV charging and will nottotally supersede any alternative charging solution (e.g., wirelesscharging). In battery swapping stations motorists can get a fullyrecharged battery perhaps in less than a minute (faster than refuelingin a conventional gas stations), while corded and wireless charging willbe the solution at home and for opportunistic charging in public andprivate parking lots to increase vehicles autonomy time.

Due to high capital expenditure issues, deployments of battery swappingstations may be mainly along major transport axis and in larger cities.Another strong argument for a decentralized and in particular for aconvenient charging and docking-to-grid solution is the availability ofBEVs for vehicle-to-grid use as explained above.

In FIG. 14, the EV replaceable battery unit 222 is accommodated in aspecially designed battery compartment 224. The battery unit 222 alsoprovides a wireless power interface 226, which may integrate the entireBEV sided wireless power subsystem comprising the resonant magneticantenna, power conversion and other control and communications functionsneeded for efficient and safe wireless energy transfer between a groundembedded charging base (CB) and the Electric Vehicle (EV) battery.

It may be useful for the BEV antenna to be integrated flush with abottom side of battery unit 222 (vehicle body) so that there are noprotrusive parts and so that the specified ground-to-vehicle bodyclearance can be maintained. This configuration may require some room inthe battery unit dedicated to the wireless power subsystem.

In some exemplary embodiments, the CB antenna and the BEV antenna arefixed in position and the antennas are brought within a near-fieldcoupling region by overall placement of the BEV relative to the CB.However, in order to perform energy transfer rapidly, efficiently, andsafely, the distance between the charging base antenna and the BEVantenna may need to be reduced to improve magnetic coupling. Thus, insome exemplary embodiments, the CB antenna and the BEV antenna may bedeployable moveable to bring them into better alignment.

Also illustrated in FIG. 14 is a battery unit 222 that is completelysealed and that provides contactless power and communications interfaces226,228. A conceptual block diagram of this exemplary embodiment isillustrated in FIG. 16.

FIGS. 15A-15D are more detailed diagrams of a loop antenna and ferritematerial placement relative to a battery. In these exemplaryembodiments, the battery unit includes a non-deployable BEV antennamodule as part of the wireless power interface. To prevent magneticfields from penetrating into the battery unit 230 and into the interiorof the vehicle, there may be a conductive shielding 232 (e.g., a coppersheet) between the battery unit and the vehicle. Furthermore, anon-conductive (e.g., plastic) layer 234 to may be used protect theconductive shield 232, the coil 236, and the ferrite material 238 fromall sorts of environmental impacts (e.g., mechanical damage,oxidization, etc.).

FIG. 15A shows a fully ferrite embedded antenna coil 236. The coil 236itself may be made, for example only, of stranded Litz wire. FIG. 15Bshows an optimally dimensioned ferrite plate (i.e., ferrite backing) toenhance coupling and to reduce eddy currents (heat dissipation) in theconductive shield 232. The coil may be fully embedded in anon-conducting non-magnetic (e.g. plastic) material 234. There may be aseparation between coil and ferrite plate in general, as the result ofan optimum trade-off between magnetic coupling and ferrite hysteresislosses.

FIG. 15C illustrates another exemplary embodiment wherein the coil maybe movable in a lateral (“x”) direction. FIG. 15D illustrates anotherexemplary embodiment wherein only the antenna (coil) module is deployedin a downward direction. The design of this deployable module is similarto that of FIG. 15B except there is no conductive shielding at theantenna module. The conductive shield stays with the battery unit. Thephysical separation of the antenna module from the battery unit willhave a positive effect on the antennas performance. However, thesolution may be more fault-prone in considering the harsh environmentalconditions below a vehicles body (pollution, icing, water).

FIG. 16 is a simplified block diagram of portions of a battery system250 in a BEV equipped to receive wireless power. This exemplaryembodiment illustrates wireless power interfaces that may be usedbetween an EV system 252, a battery subsystem 254, and the wirelesscharging interface to a CB (not shown). The battery subsystem 254provides for both energy transfer and communications with a wirelessinterface between the EV and the battery subsystem 254, which enables acompletely contactless, closed, and sealed battery subsystem 254. Theinterface may include all the required functionality for bidirectional(two-way) wireless energy transfer, power conversion, control, batterymanagement, and communications.

The charger to battery communication interface 256 and wireless powerinterface 258 has been explained above and it shall be noted again thatFIG. 16 shows a generic concept. In specific embodiments, the wirelesspower antenna 260 and the communications antenna may be combined to asingle antenna. This may also apply to the battery-to-EV wirelessinterface 262. The power conversion (LF/DC) unit 264 converts wirelesspower received from the CB to a DC signal to charge the EV battery 266.A power conversion (DC/LF) 268 supplies power from the EV battery 266 toa wireless power interface 270 between the battery subsystem 254 and theEV system 252. A battery management unit 272 may be included to manageEV battery charging, control of the power conversion units (LF/DC andDC/LF), as well as a wireless communication interface.

In the EV system 252, a wireless antenna 274 receives power from antenna276 and a LF/DC power conversion unit 278 may supply a DC signal to asuper capacitor buffer 280. In some exemplary embodiments LF/DC powerconversion unit 278 may supply a DC signal directly to the EV powersupply interface 282. In other exemplary embodiments, a contactlessinterface may not be capable of providing the high battery peak currentrequired by the vehicles drive train e.g., during acceleration. Todecrease the source resistance and thus the peak power capability of theEVs energy storage system as “seen” at the EV power supply terminals, anadditional super capacitor buffer may be employed. An EV electricalsystem control unit 284 may be included to manage control of the powerconversion unit (LF/DC) 278, charging of the super capacitor buffer 280,as well as a wireless communication interface 262 to the EV and thebattery subsystem 254. Furthermore, it is noted that V2G capabilities,as described above, may apply to the concepts described with referenceto, and illustrated in, FIG. 16.

Exemplary embodiments of the present invention, as described below, aredirected toward alignment of wireless power antennas as part of awireless charging system for BEVs (also referred to herein as a “BEVwireless charging system”). As will be appreciated by a person havingordinary skill in the art, adequate antenna alignment may enable two-way(bidirectional) energy transfer between a charging base, positionedwithin a parking space, and a BEV subsystem, in a quick, efficient, andsafe manner. According to one or more exemplary embodiments, a vehicleguidance system may provide coarse alignment for adequately positioninga BEV within a parking space to enable a CB antenna and a BEV antenna tobe aligned within a specific error radius. Furthermore, according to oneor more other exemplary embodiments, an antenna alignment system may beconfigured to mechanically adjust a position of a CB antenna, a BEVantenna, or both in one or more directions to enable for fine alignmentof antennas within a BEV wireless charging system.

FIG. 17 illustrates a parking lot 1701 comprising a plurality of parkingspaces 1707. It is noted that a “parking space” may also be referred toherein as a “parking area.” To enhance the efficiency of a vehiclewireless charging system, a BEV 1705 may be aligned along an X direction(depicted by arrow 1702 in FIG. 17) and a Y direction (depicted by arrow1703 in FIG. 17) to enable a wireless power vehicle base 1704 within BEV1705 to be adequately aligned with a wireless power charging base 1706within an associated parking space 1707. Although parking spaces 1707 inFIG. 17 are illustrated as having a single charging base 1706,embodiments of the present invention are not so limited. Rather, it iscontemplated that parking spaces may have one or more charging bases.Furthermore, embodiments of the present invention are applicable toparking lots having one or more parking spaces, wherein at least oneparking space within a parking lot may comprise a charging base.

FIG. 18 illustrates a plurality of tire stops 1801 (also commonlyreferred to as “wheel stops” or “garage stops”) that may be used toassist a vehicle operator in positioning a BEV in a parking space 1803to enable a vehicle base (e.g., vehicle base 1704; see FIG. 17) withinthe BEV to be aligned with a charging base 1802. Furthermore, accordingto one or more exemplary embodiments, global navigation systems (e.g.,GPS, Galileo), augmentation systems (e.g., satellite based or groundbased), or any combination thereof, may be used for assisting a BEVoperator in positioning a BEV to enable a an antenna within the BEV tobe adequately aligned with a charging antenna within a charging base(e.g., charging base 1706).

Furthermore, a BEV guidance system, according to other various exemplaryembodiments of the present invention, may be utilized for positioning aBEV within a parking space to adequately align associated antennas. FIG.19 illustrates a guidance system 1901 comprising at least one chargingbase 1902 positioned within a parking space 1903 and at least onevehicle base 1905 integrated within a BEV 1904. Furthermore, analignment system 1908 may be integrated within BEV 1904 and may beoperably coupled to vehicle base 1905. It is noted that charging base1902 may include one or more antennas (not shown in FIG. 19; e.g., seeFIGS. 21 and 22) and vehicle base 1905 may include one or more antennas(also not shown in FIG. 19; e.g., see FIGS. 21 and 22). As describedmore fully below, a vehicle guidance system may be based on radiopositioning and direction finding principles and/or on optical,quasi-optical and/or ultrasonic sensing methods.

FIG. 20 illustrates a block diagram of a portion of a guidance system2001, in accordance with an exemplary embodiment of the presentinvention. More specifically, with reference to FIGS. 19 and 20, portionof guidance system 2001 may comprise vehicle base 1905 operably coupledto alignment system 1908. As illustrated, alignment system 1908 mayinclude at least one processor 2002 and may be configured to visuallyconvey information to a BEV operator, audibly convey information to aBEV operator, or both, to assist the BEV operator to properly positionan associated BEV within a parking space to enable for associatedantennas to be aligned within a specific error radius. Furthermore,alignment system 1908 may comprise an autopilot system, or may beconfigured to control an autopilot system, which is configured toautomatically position an associated BEV within a parking space.

FIGS. 21 and 22 respectively illustrate examples of antennas 2101 and2201, which may be used in implementation of guidance system 1901 (seeFIG. 19). With reference to FIG. 21, antenna 2101 comprises a ferritedisk 2102 coupled to an antenna 2103. Antenna 2101 may further comprisean x-antenna magnetic element 2104 and an orthogonally orientedy-antenna magnetic element 2105. With reference to FIG. 22, antenna 2201may comprise a ferrite rod x-antenna magnetic element 2202 and a ferriterod y-antenna magnetic element 2203 that is orthogonal to ferrite rodx-antenna magnetic element 2202. Moreover, it is noted that chargingbase 1902 (see FIG. 19) may include one or more known and suitableantennas. For example only, charging base 1902 may include one or moreantennas configured for generating a polarized magnet field.Furthermore, in another example, charging base 1902 may include one ormore antennas configured for generating a rotating (i.e., circularpolarized) magnet field.

By way of example only, charging base 1902 may include at least oneantenna having orthogonal x and y magnetic elements, similar to antenna2101 or antenna 2201, as illustrated in FIGS. 21 and 22, respectively.It is noted that, according to one exemplary embodiment, the antennasconfigured for wireless power transfer may also be configured for use inthe guidance system 1901 e.g. for positioning and direction findingpurposes. According to another exemplary embodiment, charging base 1902may include one or more antennas for use within guidance system 1901 andone or more separate antennas for wireless power transmission.

With reference again to FIG. 19, and, as will be described more fullybelow, during a contemplated operation of BEV guidance system 1901,charging base 1902 may be configured to convey, via one or moretransmitters, a guidance signal 1906, which may be received by vehiclebase 1905. Upon receipt of guidance signal 1906, vehicle base 1905, and,more specifically, alignment system 1908 may be configured to utilizeinformation derived from guidance signal 1906 to assist a driver of BEV1904, a controller of alignment system 1908 (e.g., an autopilot systemcontroller), or a combination thereof, to direct BEV 1904 in an Xdirection (see arrow 1702 in FIG. 17), a Y direction (see arrow 1703 inFIG. 17), or a combination thereof, to enable at least one wirelesspower antenna of vehicle base 1905 to be adequately aligned with atleast one wireless power antenna of charging base 1902. Morespecifically, alignment system 1908 may be configured to utilizeinformation derived from guidance signal 1906 to enable at leastwireless power antenna of vehicle base 1905 to be adequately alignedwith at least one wireless power antenna of charging base 1902.

Various contemplated methods of implementing guidance system 1901 forpositioning a BEV within a parking space will now be described.According to one exemplary embodiment, charging base 1902 may beconfigured to generate one or more magnetic fields, which may bedetected by vehicle base 1905 and used for determining a direction fromvehicle base 1905 to charging base 1902. More specifically, in thisembodiment, guidance signal 1906 may comprise one or more very lowfrequency (VLF) (i.e., 3-30 KHz) or low frequency (LF) (i.e., 30-300KHz) magnetic field patterns, which may be generated by charging base1902 and received by one or more VLF or LF receive antennas of vehiclebase 1905, wherein the one or more receive antennas include orthogonal xand y components (e.g., antenna 2101 or antenna 2201). Furthermore, adirection of a horizontal field component of the magnetic field, whichpoints toward charging base 1905, may be determined from signalsreceived by the one or more receive antennas of vehicle base 1905.Stated another way, a horizontal component of a magnetic field generatedfrom at least one antenna within charging base 1905 may be detected byat least one antenna with vehicle base 1905, wherein the horizontalcomponent is directed toward the at least one antenna with vehicle base1905.

FIG. 23 illustrates a side view of a magnetic field 2301 generated bycharging base 1902. With reference to FIGS. 19 and 23, charging base1902 may generate magnetic field 2301 having a horizontal fieldcomponent 2302, which may be received by one or more antennas of vehiclebase 1905. It is noted that reference numeral 2303 depicts an offsetbetween charging base 1902 and vehicle base 1905. FIG. 24 illustrates aside view of an antenna 2402 (i.e., an antenna of vehicle base 1905) andcharging base 1902 emitting magnetic field 2301. FIG. 25 illustrates atop-down view of antenna 2402 positioned within magnetic field 2301.With reference to FIGS. 24 and 25, the direction of the flux lines 2401of magnetic field 2301 adjacent antenna 2402 (e.g., antenna 2101 orantenna 2201) of vehicle base 1905 (see FIG. 19) may be oriented along ahorizontal field component of magnetic field 2301 and in a directiontoward charging base 1902. Stated another way, the orientation of fluxlines 2401 adjacent antenna 2402 may be defined by a vector 2403, whichpoints toward the source of magnetic field 2301 (i.e., one or moreantennas within charging base 1902).

According to one exemplary embodiment, alignment system C08 (see FIGS.19 and 20) may include a processor 2002 (see FIG. 20), which may beconfigured to calculate a direction of vector 2403 from one or moresignals received from orthogonal x and y magnetic elements (e.g.,x-antenna 2104 and y-antenna 2105) of an antenna (e.g., antenna 2402) ofvehicle base 1905. Stated another way, processor 2002 may determine thevector between at least one antenna within vehicle base 1905 to at leastone antenna within charging base 1902. It is noted that a ferrite disk(e.g., ferrite disk 2102 of FIG. 21) may concentrate and/or magnify ahorizontal field component of magnetic field 2301 and, as a result, thehorizontal field component may be more easily detected.

By way of example only, charging base 1902 may be configured to generateradio wave magnetic fields, which, as will be understood by a personhaving ordinary skill in the art, may not require an unobstructed lineof sight and are not easily obstructed by objects within a surroundingenvironment (e.g., snow, pollution, or other objects). Moreover,charging base 1902 may be configured to reduce, and possibly eliminate,multi-path propagation effects (i.e., reflections from surroundingobjects). In other examples, charging base 1902 may be configured toemit or receive signals at optical or infrared frequencies.

Furthermore, according to another exemplary embodiment of determining adirection from vehicle base 1905 to charging base 1902, guidance system1901 may be configured to function in a manner similar to that of aradio navigation system (e.g., VHF Omni-directional Radio Range “VOR”),as will be understood by a person having ordinary skill in the art. Inthis exemplary embodiment, guidance signal 1906 may comprise a directionsignal (e.g., a circular polarized H-field) and a time-reference signal.Furthermore, vehicle base 1905 may be configured to receive each of thedirectional signal and the reference signal and measure a phasedifference therebetween to determine a line of position, from chargingbase 1902, on which vehicle base 1905 is located.

Additionally, for the exemplary embodiments described above related topositioning a BEV within a parking space, guidance system 1901 may beconfigured to measure a change in a strength of guidance signal 1906(see FIG. 19) emitted from charging base 1902 to determine a position ofvehicle base relative to charging base 1902. The BEV may solely use oradditionally use the gradient of the field strength of the guidancesignal to find to a location of the charging base. This may enable useof simplified receivers within the BEV. Moreover, it is noted that forthe exemplary embodiments described above related to magnetic fielddetection, a guidance system (e.g., guidance system 1901) should beconfigured to detect a magnetic field emitted from an associatedcharging base without being affected by the presence of magnetic fieldsproduced by adjacent charging bases for the purpose of wireless energytransfer, for the purpose of vehicle guidance, or both.

Furthermore, exemplary embodiments of the present invention includedevices, systems and methods for employing ultra wide band (UWB)location technologies. Ultra wide band localizers may be based ondistance measurement through measurement of a round-trip time of a pulseor other suitable wideband waveforms, similarly to secondarysurveillance radar used in air traffic control or satellite rangingtechniques. In an exemplary embodiment, multiple UWB transponders aspart of the charging base are suitably positioned within a parking lotarea and there is one UWB transceiver as part of the BEV subsystemhaving an antenna suitably installed e.g. within the BEV wireless powerantenna. The BEV transceiver emits a UWB signal which when received bythe UWB transponders triggers a response signal in each of thetransponders. These response signals are preferably of the same waveformbut delayed in time by a fixed and known amount or shifted in frequencyor both, relative to the received signal. The BEV transceiver in turnmeasures time of arrival of all response signals and determinesround-trip-time and related distance between its UWB antenna and each ofthe transponders. For example, by positioning multiple ranging deviceswithin charging base 1902, a position of charging base 1902 relative tovehicle base 1905 may be determined through triangulation methods, aswill be understood in the art. Ultra wide band location technologies mayenable real-time, continuous position measurements with resolutions inthe centimeter range. Moreover, code and time division channelizationfor a million localizers per km2 may be achievable. FIG. 26 illustratesfour ultra wide band transponders for use within a triangulationprocess.

In yet another exemplary embodiment using UWB guidance signals, there isa UWB transmitter as part of the charging base having an antennasuitably placed e.g. within the CB wireless power antenna and there aremultiple UWB receivers as part of the BEV subsystem having antennassuitably placed on the BEV. The BEV-sided guidance system measuresrelative time of arrival of the UWB signal in each of its receivers todetermine an angle of direction pointing to the charging base.

Above described methods using UWB electromagnetic signals forpositioning or direction finding may also apply to the use of acoustice.g. ultrasonic signals, emitters and sensors.

With reference again to FIG. 17, it is noted that each non-activecharging base 1706 may be configured to emit a beacon signal at a verylow frequency (VLF) (i.e., 3-30 KHz) or a low frequency (LF) (i.e.,30-150 KHz) and in a different frequency band in which wireless power istransmitted. Furthermore, each beacon signal may comprise a parkingspace identifier indicative of the parking space from which the beaconsignal originated. This beacon signal may be identical with the guidancesignal used for positioning or direction finding purposes. Moreover,beacon signals emitted by charging bases 1706 may share availableresources in time, frequency, or both. Moreover, for the exemplaryembodiments described above, a guidance system (e.g., guidance system1901) may be configured to operate in a single, isolated parking space(e.g., a residential garage) and may not require use of triangulationmethods involving charging bases of adjacent parking spaces.

FIG. 27 is a flowchart illustrating a method 2701, in accordance withone or more exemplary embodiments. Method 2701 may include generating atleast one signal with at least one antenna positioned within a wirelesscharging base (depicted by numeral 2702). Method 2701 may furtherinclude detecting at least a portion of the at least one signal with atleast one antenna within a wireless vehicle base integrated within abattery electric vehicle (BEV) (depicted by numeral 2703). Further,method 2701 may include determining a direction from the vehicle base tothe charging base from the detected at least a portion of the at leastone signal (depicted by numeral 2704). Moreover, method 2701 may includemoving the battery electric vehicle (BEV) toward the wireless chargingbase according to the determined direction (depicted by numeral 2705).

The various exemplary embodiments described above with reference toFIGS. 17-27 may enable antennas within a BEV wireless charging system tobe aligned within an error radius. In the event a residual antennaalignment error exists after a BEV has been positioned within a parkingspace, devices, systems, and methods related to fine alignment ofantennas, as described below, may be utilized.

A wireless power charging and antenna alignment system includes acharging base configured to transmit or receive a wireless power signalto/from a BEV wireless charging subsystem. The BEV wireless chargingsubsystem may be operably coupled with a battery unit of a BEV. Thesystem further includes a BEV antenna operably coupled with the BEVwireless charging subsystem. The system may further include a mechanicaldevice configured for adjusting a physical position of the BEV antennaas described herein.

The BEV antenna may be positioned in a location of the BEV where thereis enough space to integrate the BEV wireless charging subsystem withthe other components and systems of the BEV. For example, the wirelesspower antenna may be located within the underside of the chassis of theBEV. The BEV antenna may be positioned near the front, center, or rearof the BEV. Positioning the wireless power antenna near the front of theBEV may result in the driver having more accuracy in positioning, as thewireless power antenna would be closer to the BEV's steering unit.Additionally, locating the wireless power antenna near the front of theBEV may provide more uniformity for overly long BEVs. Positioning thewireless power antenna near the center of the BEV may result in havingmore flexibility in parking forwards or backwards. Positioning thewireless power antenna near the rear of the BEV may be advantageous forsystem integration due to space constraints in the front and middlesections of the BEV. Other benefits for positioning the wireless powerantenna near the front, middle, or rear of the BEV may also exist.

FIG. 28A illustrates that various obstructions 2805 may be encounteredby a BEV 2810 requiring a minimum chassis clearance. The obstructions2805 may contact the underside 2815 of the chassis of the BEV 2810 atdifferent locations. When a wireless power antenna (not shown) islocated within or near the underside 2815 of the chassis of the BEV2810, the wireless power antenna may become damaged, misaligned, or haveother problems associated with obstructions 2805 contacting the wirelesspower antenna.

FIGS. 28B and 28C illustrate a BEV antenna 2820 according to anexemplary embodiment of the present invention. In order to protect theBEV antenna 2820 from undesirable contact from obstructions, it may bedesirable to locate the BEV antenna 2820 within a cavity 2812 of theunderside of the chassis of a BEV 2810. In order to further protect thewireless power antenna 2820 from environmental effects (e.g., pollution,dirt, mud, water, ice, moisture), a cover 2824 and/or defrost unit 2822may be used. The defrost unit 2822 may be the wireless power antennaitself. In this concept the BEV wireless power subsystem may be operatedin transmit mode injecting a current into the BEV antenna 2820 thatproduces sufficient heat dissipation.

A charging base (not shown) may include a power conversion unit operablycoupled with a CB antenna. The charging base may further include othermechanical or electronic components (e.g., processor) that may be usedfor position adjustment of the CB antenna as will be described herein.Components of the charging base may be housed within a charging basethat is at least partially embedded below a ground surface, such as in aparking lot, driveway, or garage. A tool may be used to form the hole inwhich the charging base is located. For example, FIG. 29A illustrates atool 2900 (e.g., milling cutter) which may be used to drill a hole inthe ground 2905, in which a charging base may be at least partiallyembedded. As a result, the tool 2900 may be used to equip parking lotswith charging bases in order to accelerate large scale deployments ofwireless charging of BEVs.

FIG. 29B illustrates a charging base 2910 at least partially embeddedbelow a ground surface 2905 according to an exemplary embodiment of thepresent invention. The charging base 2910 may include one or more CBantennas 2915 for transmitting or receiving a wireless power signalto/from a corresponding BEV antenna (not shown) associated with a BEV.The charging base 2910 may be protrusive 2901 from the ground, which mayimprove coupling as the distance between the CB antenna 2915 and BEVantenna may be reduced. A protrusive 2901 charging base 2910 may be moreaccessible for maintenance and repair. However, a protrusive 2901charging base 2910 may be an impediment, such as for pedestrians orduring snow removal. Alternatively, the charging base 2910 may be flush2902 with the surface of the ground 2905. A flush 2902 charging base2910 may be more accessible for maintenance and repair andnon-impedimental; however, coupling between the CB antenna 2915 and BEVantenna may be reduced in comparison to the protrusive 2901 chargingbase 2910. A flush 2902 charging base 2910 may also leave a potentialproblem with the edge of the ground surface (e.g., asphalt) potentiallybeing more prone to erosion by water, ice and mechanical stress.Alternatively, a charging base 2910 may be located completely below 2903the surface of the ground (e.g., below the asphalt layer 2907). Such abelow-surface 2903 charging base 2910 may be more secure from intruders(e.g., vandalism), and be non-impedimental; however, coupling andaccessibility to maintenance and repair may be reduced. With referenceto FIG. 29D, a substantially flat cover 3535 with a thin collar 3537extending over a ground surface 3539 (e.g., asphalt) may be positionedover charging base 2910 and may enable unimpeded road cleaning (e.g.,machined road cleaning). Furthermore, cover 3535 may solve the problemdescribed above related to potential erosion of an edge of the groundsurface 3539.

FIG. 29C further shows a charging base 2910 that is located fully belowthe surface of the ground 2905 according to an exemplary embodiment ofthe present invention. The charging base 2910 may be configured toprotect the wireless power antenna 2915 from environmental factors 2908,such as heat, cold, solar radiation, water, moisture, debris, etc. Forexample, such a fully embedded charging base may be hermetically sealedin order to be water proof.

FIG. 30A-30C illustrate a BEV 3010 including a wireless power antenna3015 positioned over a charging base 3020 also including a wirelesspower antenna 3025. As shown in FIG. 30, the BEV antenna 3010 and the CBantenna 3025 are aligned in the X and Y directions, and separated by adistance 3030 in the Z direction. As shown in FIG. 30B, the BEV antenna3010 and the CB antenna 3025 are misaligned by an offset distance 3035in the X direction, and are separated by a distance 3030 in the Zdirection.

It may be desirable to reduce the distance 3030 and the offset distance3035 in order to improve coupling strength between the BEV antenna 3015and the CB antenna 3025. Reducing the distance 3030 and the offsetdistance 3035 may occur through a fine alignment adjustment system.

The fine alignment adjustment system may be used to adjust the physicalposition of the CB antenna 3025, the BEV antenna 3015, or a combinationthereof in order to increase coupling strength between the CB antenna3025 and the BEV antenna 3015. Adjusting the position of one or both ofthe BEV antenna 3015 and CB antenna 3025 may be performed in response toa detection of misalignment therebetween. Determining misalignment maybe performed by utilizing information from the vehicle guidance system,as described above, such as for the methods related to magnetic fielddetection. Furthermore, information from a wireless power link (e.g.,various parameters indicative of the performance of the wireless powerlink) may be used in determining misalignment of associated antennas.For example, during misalignment detection, the wireless power link maybe operated at a reduced power level and after associated antennas havebeen accurately aligned, the power level may be increased.

The fine alignment adjustment system may be separate from, or inaddition to the course alignment guidance system. For example, thecourse alignment guidance system may guide a BEV into a position withina given tolerance (i.e., error radius), such that a fine alignmentadjustment system can correct for fine errors between the BEV antenna3015 and the CB antenna 3025.

As shown in the overhead view of BEV 3010 in FIG. 30C, the BEV antenna3010 and the CB antenna 3025 are misaligned only in the X direction. TheBEV antenna 3010 and CB antenna 3020 are aligned in the Y direction. Forexample, the alignment in the Y direction may have been accomplished bythe BEV 3010 using its own traction system, which may be assisted (e.g.,auto-piloted) by the guidance system described herein, and by which theBEV's motor may be able to move smoothly and accurately to a target Yposition. In such a scenario, alignment error in the X direction maystill exist but not in the Y direction. Eliminating the need foralignment adjustment in the Y direction (e.g., through use of a coursealignment guidance system) may also reduce space requirements for BEVantenna 3015 as the BEV antenna 3015 may be configured to move only in Xdirection, which may be accommodated in a cavity and not deployed forwireless power transfer. Thus, eliminating the need for fine alignmentin the Y direction may simplify the BEV wireless power subsystem.

FIGS. 31A-31G illustrate several variants for fine alignment adjustmentaccording to various exemplary embodiments of the present invention. Asshown by FIGS. 31A-31G, the physical position of the BEV antenna 3115may be adjusted to correct for alignment errors in the X, Y, and Zdirections, or any combination thereof. Additionally, the position ofthe CB antenna 3125 may be adjusted to correct for alignment errors inthe X, Y, and Z directions, or any combination thereof. In someexemplary embodiments, the positions of both the BEV antenna 3115, andthe CB antenna 3125 may be adjusted to correct for alignment errors inany of the X, Y, and Z directions, or any combination thereof.

Stated another way, during coupling wireless power between a CB antenna3125 and a BEV antenna 3115 associated with a battery unit of a BEV3110, the position of at least one of the CB antenna 3125 and the BEVantenna 3115 may be adjusted. The adjustment of position may beinitiated in response to a detection of misalignment between the CBantenna 3125 and the BEV antenna 3115. A charging base 3120 may includea wireless power transmitter configured to transmit the wireless powersignal, and a CB antenna 3125 operably coupled with the wireless powertransmitter. One or more mechanical devices may be used for adjustingthe position of the BEV antenna 3115 and/or the CB antenna 3125 in atleast one of an X, Y, and Z direction.

FIG. 32 illustrates possible locations in the X and Y direction that amechanical device may adjust the position of a BEV antenna according toan exemplary embodiment of the present invention. For example, byselecting an angle pair (α, β) within the mechanical device, anyposition in the X and Y directions may be achieved within a radius rmax.

FIG. 33 illustrates a mechanical solution for a BEV antenna 3315 that islocated within a cavity 3312 of the underside of a BEV 3310 according toan exemplary embodiment of the present invention. As shown in FIG. 33,mechanical device 3350 may adjust the position of the BEV antenna 3315in the X and Y directions by selecting an appropriate angle pair (α, β).Additionally, mechanical device 3350 may adjust the position of the BEVantenna 3315 in the Z direction by lowering the BEV antenna 3315 fromthe cavity 3312 of the BEV 3310. Mechanical device 3350 may include oneof many mechanical solutions including electric driven mechanics and/orhydraulics. Although not shown herein, a mechanical device may similarlybe used to adjust the position of the CB antenna in the X, Y, or Zdirections, or any combination thereof. In other words, fine alignmentadjustment may be accomplished with a mechanical solution for adjustingthe position of the CB antenna, the BEV antenna 3315, or both, as thecase may be. Some mechanical solutions may experience failure and mayrequire some maintenance or repair.

FIG. 34 illustrates another mechanical solution in which the BEV antenna3415 (and/or CB antenna) may be repositioned by a gear shaft 3450operably coupled to a drive mechanism 3452 according to an exemplaryembodiment of the present invention. In operation, if the drivemechanism 3452 is actuated, the gear shaft 3450 may be rotated to extendthe support member 3454 in order to lower the BEV antenna 3415 in the Zdirection.

As shown in FIG. 35A, a charging base 3520 may experience heavy loadingfrom the weight of a BEV 3510. Therefore, it may be desirable for thecharging base 3520 to further include a reinforced cover 3527. FIGS. 35Band 35C illustrate a charging base 3520 including a reinforced coveraccording to an exemplary embodiment of the present invention. Areinforced cover 3527 may be located above the surface of the ground asshown in FIG. 35B, or below the surface of the ground as shown in FIG.35C. The reinforced cover 3527 may increase the distance from a BEVantenna than would otherwise occur with a charging base 3520 notincluding the reinforced cover. Being above the surface of the groundmay improve accessibility for maintenance and repair, but may also be anobstruction (e.g., for pedestrians, snow clearance, etc.). In anexemplary embodiment with the CB antenna 3525 located within an embeddedcharging base 3520 and with the CB antenna 3525 configured to be movablewithin the embedded charging base 3520, it may be desirable for thecharging base 3520 to be enlarged in comparison to a charging base witha stationary CB antenna.

Up to this point a wireless power charging and antenna alignment systemfor a BEV has been shown to move only the BEV antenna in the X, Y, and Zdirections. FIGS. 36A-36D illustrate a BEV 3610 including a wirelesspower battery unit 3630 and the BEV antenna 3615 configured to berepositioned in the X, Y, and Z directions in various combinationsaccording to an exemplary embodiment of the present invention. Thebattery unit may be located within a cavity of the BEV 3610.Additionally, the BEV antenna 3615 may be located within a cavity of thebattery unit 3630.

Adjusting the position of the entire battery unit 3630 (e.g., in the Zdirection) to accommodate antenna alignment, decrease the distancebetween the antennas, or both, may improve coupling between the CBantenna 3625 and BEV antenna 3615.

For example, the position of the battery unit may 3630 may be adjustedin one or more directions (FIG. 36B). The BEV antenna 3615 may be movedin the X, Y, and Z directions (FIG. 36C). Additionally, both the batteryunit 3630 and the BEV antenna 3615 can be moved in the X, Y, and Zdirections in various combinations (FIG. 36D). Like with the examplesdiscussing adjusting the position of an antenna, adjusting the positionof the battery unit 3630 may be accomplished through mechanical devices(e.g., through electric driven mechanics and/or hydraulics).

The fine alignment adjustment may also accomplished with the assistanceof an electrical solution (e.g., electronically switched coil arrays)altering the flux lines of the electric field generated by the wirelesspower transmitter. A combination of mechanical and electrical alignmentof the antennas may be used.

The fine alignment adjustment may also be performed using the BEV's 3610own traction system, which may configured to have the motor move the BEV3610 smoothly and accurately (e.g., by moving the BEV 3610 back andforth in a zig-zag motion) to enhance coupling between coupling betweenthe CB antenna 3625 and BEV antenna 3615. This zig-zag motion may beperformed fully automatically by the BEV 3610 without, or with onlyminimum, operator intervention. For example, the BEV 3610 may beequipped with a servo steering wheel, ultrasonic sensors, and artificialintelligence. In this case the BEV antenna 3615 may be fixed, andadjustment of the BEV antenna 3615 through other mechanical orelectrical solutions may not be required. In other words, the BEVantenna 3615 is in a fixed position in at least one of the X, Y, and Zdirections (or all directions) in relation to the BEV 3610, and themechanical device used to adjust the position of the BEV antenna 3615includes the motor of the BEV 3610 configured for controllablypositioning the BEV 3610 for adjusting the position of the BEV antenna3615 in at least one of the X, Y, and Z directions.

Stated another way, a wireless power alignment system for a vehicle maycomprise a wireless power receiver configured to receive a wirelesspower signal, the wireless power receiver may be operably coupled with abattery unit 3630 of a BEV 3610. The BEV antenna 3615 may be operablycoupled with the wireless power receiver, and at least one mechanicaldevice may be configured for adjusting a position of the BEV antenna3615 in at least one of an X, Y, and Z direction. Adjusting a positionof the BEV antenna may be in response to a detection of misalignmentbetween the BEV antenna 3615 and a CB antenna 3625.

FIG. 37 illustrates fine alignment adjustment for a wireless powercharging system 3700 for a BEV 3710 according to an alternativeexemplary embodiment of the present invention. Wireless power system3700 includes a BEV 3710 associated with a BEV side wireless powersubsystem 3713 operably coupled to a power supply 3718 (e.g., battery).The BEV wireless power subsystem 3713 may include a BEV power converter(not shown) operably coupled with a BEV antenna 3715. The BEV antenna3715 may be located along the underside of the chassis of BEV 3710. Thewireless power system 3700 for a BEV 3710 further includes a chargingbase 3720 including a CB power conversion (not shown) operably coupledwith a BEV antenna 3725. Rather than the charging base 3720 being atleast partially embedded below the surface of the ground as previouslydescribed, charging base 3720 may be configured as a charging platformlocated above the surface of the ground. Such a configuration may bedesirable as a retrofit solution for a garage or carport if forming ahole in the ground for a charging base is undesired. A configuration ofa charging platform may also provide flexibility as the chargingplatform may mobile and able to be stored in a location other than agarage or transferred to another location.

The charging base 3720 (e.g., charging platform) may be configured tomove automatically (e.g., as an automated robot), be controlled remotely(e.g., via a remote control unit), or through other methods for controlof a mobile charging platform. For example, the BEV 3710 (e.g., throughits wireless power subsystem 3713) may request a charge, whereupon thecharging base 3720 may move automatically underneath the BEV 3710 andposition itself to align the CB wireless power antenna 3725 with the BEVantenna 3715. Further fine alignment (if necessary) may be accomplishedthrough adjusting the position of the BEV antenna 3715 and CB antenna3725 in one or more direction as previously described.

Once sufficiently aligned, charging base 3720 may more efficientlytransfer wireless power between a charging base and a wireless powersubsystem 3713 of the BEV 3710. After charging is completed, or aftersome other event, the charging base 3720 may return back to a waitingposition (standby mode). The wireless power system 3700 may, therefore,include a communication link with the charging base 3720 and anotherdevice (e.g., wireless power subsystem 3713) associated with the BEV3710. The charging base 3720 may further include cable management inorder to uncoil and coil a connecting cable 3722 prior to and after thecharging process.

A wireless power charging system for a BEV may be further configured forsafety and security concerns. For example, the BEV may be configured tobe immobilized when the wireless power BEV or CB antennas are deployed,when such antennas cannot be retracted (e.g., due to damage orobstacle). Such immobilization may protect the wireless power chargingsystem from further damage. The wireless power charging system mayfurther include sensors that detect mechanical resistance of thewireless power BEV or CB antennas. Detecting mechanical resistance mayprotect the wireless power BEV or CB antennas and accompanyingcomponents from being damaged if an obstacle (stone, debris, snow,animal, etc.) is positioned in a location that would restrict themovement of the antenna.

The wireless power charging system may further include continuousmonitoring of the wireless power link between the BEV antenna and CBantenna (e.g., monitoring voltages, currents, power flow, etc.) andreduce the power transmitted or shut down power in the event ofdetection of an abnormality in the wireless power link. The wirelesspower charging system may further include sensors configured to detectthe presence of persons or animals in close proximity of the antenna.Such sensors may be desirable in order for a processor to reduce orterminate wireless power transmission if a person is proximate thewireless power antennas. Such an action may be a safety precautionagainst prolonged exposure to electromagnetic radiation, such as forexample, while a person performs maintenance or other repair workunderneath the BEV particularly for persons using cardiac pacemakers orsimilar sensitive and safety critical medical devices.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the exemplary embodiments disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the exemplary embodiments of the invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the exemplary embodiments disclosed herein may beimplemented or performed with a general purpose processor, a DigitalSignal Processor (DSP), an Application Specific Integrated Circuit(ASIC), a Field Programmable Gate Array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theexemplary embodiments disclosed herein may be embodied directly inhardware, in a software module executed by a processor, or in acombination of the two. A software module may reside in Random AccessMemory (RAM), flash memory, Read Only Memory (ROM), ElectricallyProgrammable ROM (EPROM), Electrically Erasable Programmable ROM(EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any otherform of storage medium known in the art. An exemplary storage medium iscoupled to the processor such that the processor can read informationfrom, and write information to, the storage medium. In the alternative,the storage medium may be integral to the processor. The processor andthe storage medium may reside in an ASIC. The ASIC may reside in a userterminal. In the alternative, the processor and the storage medium mayreside as discrete components in a user terminal.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosed exemplary embodiments isprovided to enable any person skilled in the art to make or use thepresent invention. Various modifications to these exemplary embodimentswill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other embodiments withoutdeparting from the spirit or scope of the invention. Thus, the presentinvention is not intended to be limited to the exemplary embodimentsshown herein but is to be accorded the widest scope consistent with theprinciples and novel features disclosed herein.

1. An apparatus, comprising: a wireless power charging base includingpositioned within a vehicle parking space; and at least one antennaconfigured to generate a magnetic field for guiding an electric vehiclewithin the vehicle parking space and for causing a vehicle base of theelectric vehicle to align with the wireless power charging base, whereinthe at least one antenna comprises an x-antenna magnetic element and ay-antenna magnetic element orthogonal to the x-antenna magnetic element.2-7. (canceled)
 8. The apparatus of claim 1, wherein the at least oneantenna is configured to generate the magnetic field as a rotatingmagnetic field. 9-11. (canceled)
 12. The apparatus of claim 8, whereinthe rotating magnetic field comprises a circular polarized magneticfield.
 13. The apparatus of claim 1, wherein the at least one antenna isfurther configured to transfer wireless charging power.
 14. Theapparatus of claim 1, wherein the magnetic field includes a timereference signal.
 15. The apparatus of claim 1, wherein the magneticfield is generated at a frequency in a frequency band different from afrequency at which the wireless power charging base provides wirelesspower.
 16. The apparatus of claim 1, wherein the magnetic field is oneof a very low frequency (VLF) magnetic field pattern and a low frequency(LF) magnetic field pattern.
 17. The apparatus of claim 1, wherein themagnetic field includes a beacon signal conveying an identifierindicative of the parking space from which the beacon signal originates.18. An apparatus comprising: a wireless power transfer base configuredto wirelessly transmit or receive power transferred between a power gridand an electric vehicle; and at least one antenna structure comprisingan x-antenna magnetic element and a y-antenna magnetic elementorthogonally disposed to the x-antenna magnetic element, the at leastone antenna structure configured to generate or receive information viaa magnetic field, information to guide the electric vehicle to and alignthe electric vehicle with a location within a parking space, themagnetic field comprising a horizontal component indicative of adirection from the electric vehicle to the location.
 19. The apparatusof claim 18, wherein the wireless power transfer base is a wirelesspower receiving base mounted to the electric vehicle.
 20. The apparatusof claim 18, wherein the wireless power transfer base is a wirelesspower transmitting base disposed at the location within the parkingspace.
 21. The apparatus of claim 18, wherein the at least one antennastructure is further configured to wirelessly transfer the power. 22.The apparatus of claim 18, wherein the at least one antenna structure isconfigured to generate the magnetic field as a rotating magnetic field.23. The apparatus of claim 18, wherein the magnetic field includes atime reference signal.
 24. The apparatus of claim 18, wherein themagnetic field is generated at a frequency in a frequency band differentfrom a frequency at which the wireless power transfer base transferswireless power.
 25. The apparatus of claim 18, wherein the magneticfield is one of a very low frequency (VLF) magnetic field pattern and alow frequency (LF) magnetic field pattern.
 26. The apparatus of claim18, wherein the magnetic field includes a beacon signal conveying anidentifier indicative of the parking space from which the beacon signaloriginates.
 27. A method of guiding an electric vehicle within a vehicleparking space to align a wireless power receiving base with a wirelesspower transmitting base configured to wirelessly transfer power betweena power grid and the electric vehicle, the method comprising: generatinga magnetic field via at least one antenna, the at least one antennacomprising an x-antenna magnetic element and a y-antenna magneticelement orthogonally disposed to the x-antenna magnetic element; andtransmitting, via the magnetic field, information to guide the electricvehicle within the vehicle parking space and align the wireless powerreceiving base with the wireless power transmitting base, the magneticfield comprising a horizontal component indicative of a direction fromthe wireless power receiving base to the wireless power transmittingbase.
 28. The method of claim 27, wherein the at least one antenna islocated in the wireless power receiving base.
 29. The method of claim27, wherein the at least one antenna is located in the wireless powertransmitting base.
 30. The method of claim 27, further comprisingtransmitting power wirelessly via the at least one antenna.
 31. Themethod of claim 27, wherein generating the magnetic field comprisesgenerating a rotating magnetic field for guiding the electric vehicle.32. The method of claim 27, wherein the magnetic field includes a timereference signal.
 33. The method of claim 27, wherein the magnetic fieldis generated at a frequency in a frequency band different from afrequency at which the wireless power transmitting base provideswireless power.
 34. The method of claim 27, wherein the magnetic fieldis one of a very low frequency (VLF) magnetic field pattern and a lowfrequency (LF) magnetic field pattern.
 35. The method of claim 27,wherein the magnetic field includes a beacon signal conveying anidentifier indicative of the vehicle parking space from which the beaconsignal originates.